Fix pagebreak feature that currently broke last quarto release for qmd with knitr

[cderv]

This was first reported in https://community.rstudio.com/t/error-while-rendering-first-quarto-document/135656/6
I can reproduce this error by rendering hello.qmd with latest github release of quarto 0.9.324

Error running filter C:/Users/chris/scoop/apps/quarto/current/share/filters/rmarkdown/pagebreak.lua:
cannot open C:/Users/chris/scoop/apps/quarto/current/share/filters/rmarkdown/pagebreak.lua: No such file or directory

The distribution does not bundle anymore the lua filter, which breaks the Pandoc rendering.

I see this morning that there was some work yesterday on pagebreak by @cscheid, which was reverted at some point. (3f03dbc, 263380c, faeaf59, e47e54f which all follow #740). Except for the prepare-dist.ts change. This PR fixes this by putting back the rmarkdown pagebreak filter in the distribution.

I did not found PR for the pagebreak feature, so less easy to revert everything, but I think this is the last change missing to be revert.

@jjallaire I don't know yet how to build a new release so I am doing this PR for you to see and rebuild a working release.

Regarding pagebreak feature, I adapted the filter for rmarkdown, so you need help making it work more generally for all format, do not hesitate.

[jjallaire]

Thanks! Glad you caught this! I'll ping you later on this morning about plans for pagebreak -- in short we want to make it work as a shortcode (e.g. {{< pagebreak >}}) but still keep the rmarkdown-style variant for compatibility. I'll be doing some work soon to make shortcodes more extensible which will open up this possibility.

[cderv]

Ok great - shortcodes syntax is a nice one! I would probably have used that in rmarkdown in the first place if we had thought more about this.